Question

Caffeine is a compound found in coffee and tea. The percentage composition of caffeine is 49.5% carbon, 5.1% Hydrogen, 16.5%Oxygen and 28.9% Nitrogen. The relative molecular mass of caffeine is 195. Please determine:
A) The empirical formula of caffeine.
B) The molecular formula of caffeine

Answer 1

Answer:

C4H5N2O= empirical formula

C8H10N4O2= molecular formula

Explanation:

Answer 2

Answer:

Elements. C. H. 0. N

Mass(%). 49.5 5.1 16.5 28.9

Moles. =49.5/12. =5.1/1. =16.5/1 =28.9/14

=4. =5. =1. =2

Empirical Formula =C4H5N2O

n=relative molecular mass of caffeine /Mr of caffeine from empirical formula

=195/4(12)+1(5)+2(14)

=195/81

2

Molecular formula=(C4H5N2O)×2

=C8H10N4O2